In the European Union, most countries exempt biofuels from some gas taxes and impose an average tariff equal to more than $0.70 per gallon of imported ethanol.

Robert Zoellick, president of the World Bank, said on Thursday that while people in developed nations complained about the high cost of fuel to run their cars, poor people in developing nations were struggling to feed themselves.

"In many developing countries, the poor spend up to 75 per cent of their income on food. When prices of basic foods rise, it hits hard", he said.

"In just two months, rice prices have skyrocketed to near historic levels, rising by around 75 per cent globally and more in some markets - with more to come."

Growing emergency

Zoellick said the world needs to recognise that food price inflation is contributing to a growing emergency.

The UN World Food Programme has said it requires $500m just to fill immediate need.